xxxiv Aiinnal Report of the Council. 



interested rather in general principles and in the attainment of 

 comprehensive points of view than in the details of calculation, 

 he was led to scrutinize the methods of gravitational Astronomy 

 and of Mathematical Physics in general, and was enabled to 

 throw new light on questions which seemed to have attained 

 the limits of their possible development. To Astronomy in 

 particular he has given a new impetus by his theory of 

 " Periodic Orbits," and the treatise on Celestial Mechanics, in 

 which his researches are set forth, is held by competent judges 

 to mark a step forward in the science as decisive almost as that 

 made by Laplace. Not that his investigations have lightened in 

 any degree, or simplified, the ordinary calculations of Astronomy, 

 but they have pointed out the directions in which further light 

 is to be sought on the evolution and the destinies of the 

 planetary system. The catholicity of his sympathies and his 

 grasp of [general theories are shown also by the interest which 

 he took in modern theories of electricity, which he has subjected 

 to a profound and exhaustive examination. To men of science, 

 outside the ranks of professed mathematicians, as well as to a 

 wider circle, he is known by the collections of essays which he 

 has published from time to time on questions of scientific 

 philosophy, ranging from the foundations of mathematics to the 

 latest cosmical and electrical speculations. Though dealing with 

 almost all the profound questions of which he was a master, 

 they are written in an easy and almost popular style, and illu- 

 minated by brilliant flashes of humour. 



The external facts of his life are simple. He was born at 

 Nancy on April 29th, 1854, of a distinguished Lorraine family; 

 the actual President of the French Republic, for instance, 

 M. Raymond Poincare, is a near relative. He was educated 

 partly at Nancy and partly at the Ecole Polytechnique and the 

 Ecole des mines in Paris. He became Professor of Analysis at 

 Caen, and subsequently occupied in succession various chairs of 

 Mathematics in Paris. The various ofificial or advisory posts 

 which he held, and the academical and other distinctions which 



